The influence of an occipito-posterior malposition on the biomechanical behavior of the pelvic floor

• Published in: European journal of obstetrics & gynecology and reproductive biology Vol. 144; pp. S166 - S169
• Main Authors: Parente, M.P.L, Jorge, R.M. Natal, Mascarenhas, T, Fernandes, A.A, Martins, J.A.C
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Shannon Elsevier Ireland Ltd 01-05-2009; Elsevier
• Subjects: Biological and medical sciences; Biomechanical Phenomena; Computer Simulation; Delivery, Obstetric; Female; Finite Element Analysis; Finite Element Method; Gynecology. Andrology. Obstetrics; Humans; Labor Presentation; Malposition; Medical sciences; Muscle Strength - physiology; Nephrology. Urinary tract diseases; Obstetrics and Gynecology; Pelvic Floor - physiology; Pelvic floor disorders; Pregnancy; Prolapse; Simulation; Stretch; Urinary incontinence; Urinary system involvement in other diseases. Miscellaneous; Urinary tract. Prostate gland; Urinary incontinence; Simulation; Finite Element Method; Stretch; Pelvic floor disorders; Prolapse; Malposition; Urinary system disease; Gynecology; Urogenital system diseases; Urinary tract disease; Method; Perineum; Obstetrics; Prolapsus; Voiding dysfunction; Pelvic floor; Posterior; Bladder disease; Behavior
• ISSN: 0301-2115; 1872-7654
• DOI: 10.1016/j.ejogrb.2009.02.033

Abstract Objectives Contribute to the clarification of the mechanisms behind pelvic floor disorders related to a vaginal delivery. Verify the effect of an occipito-posterior malposition of the fetus during delivery on the stretch values when compared to the normal occipito-anterior position. Study design A numerical simulation based on the Finite Element Method was carried out. The Finite Element Model intends to represent the effects that the passage of a fetal head can induce on the muscles of the pelvic floor, from a mechanical point of view. The model used for the simulation represents the pelvic bones, with the attached pelvic floor muscles and the fetus. In this work the movements of the fetus during birth, in vertex position, with the fetus presenting in an occipito-posterior malposition were simulated. The results obtained were compared with a simulation in which the fetus presents in the normal occipito-anterior position. Results A maximum stretch value of 1.73 was obtained in the numerical simulation conducted on this work, where the occipito-posterior malposition was simulated. Conclusion During a vaginal delivery, the levator ani muscle and the pubococcygeus muscle are the muscles that are subjected to the largest values of stretch and strain. These muscles are the ones at greater risk for a stretch related injury. When compared to the normal occipito-anterior position, the occipito-posterior malposition produces substantially higher stretch vales for the pelvic floor muscles, increasing the risk for a stretch related injury.